Do tight shoulders limit your backbends? When you reach your arms high overhead, do your lower ribs stick out in front? Do you feel a pinching sensation on top of your shoulders when you practice Downward-Facing Dog Pose (Adho Mukha Svanasana)? If you answered yes to any of those questions, the problem might be tight latissimus dorsi muscles.

These muscles connect your upper arms to your lower back. When you raise your arms overhead, the “lats” stretch, so tight lats make it difficult to reach up. Stretching them is not hard, but the best way to do it effectively is not always obvious. Learning how to loosen your lats is worthwhile, though, because it will improve your range of motion in every yoga pose that requires you to lift one or both arms above your head. What’s more, looser lats can make it easier to do everyday activities such as changing a light bulb or getting things off a high shelf, and can even help protect you from rotator cuff injuries.

To find out how tight or loose your latissimus dorsi muscles are, try this test (if you have a shoulder injury, do not do the exercises in this article unless you are under qualified supervision). Lie on your back on the floor with your arms by your sides. Feel where the back of your rib cage touches the floor, taking special note of the point of contact that lies closest to your waist. Turn your palms up, then lift your arms up and overhead to the floor, or as close to the floor as they will go without you bending your elbows or separating your arms wider than your shoulders. For most people, this movement will make the lower ribs lift off the floor in back and jut out in front. Now return your arms to your sides and repeat the same actions, but this time, as you reach overhead, press the lower rib cage—the point closest to your waist—firmly into the floor to prevent it from lifting up at all. This will probably create a sensation of stretch on the outer sides of your armpits and make it harder to reach the floor. The stronger the stretch and the greater the restriction of movement, the tighter your lats are (although other tight muscles may increase the limitation).

Locate Your Lats

To understand what’s going on here, you first have to know where the latissimus dorsi attaches to your body. The latissimus is a broad, flat sheet of muscle whose lower end connects to your back in several places, including the vertebrae of the middle and lower spine, the sacrum (the bone that joins the spine to the pelvis), the upper rim of the pelvis alongside the sacrum, and the back of the lower four ribs. (In some people the muscle also attaches to the lower tip of the shoulder blade, making the shoulder extra tight.) The muscle fibers of the latissimus dorsi run upward and forward around the side of the trunk, where they bunch together and twist into a large bundle that forms part of the rear wall of the armpit. From there, the fibers run toward the front of the body (between the upper arm bone, or humerus, and the upper rib cage if your arms are by your sides), then wind partway around the arm bone to attach on the front of it, where it meets the shoulder. (You can’t see this attachment to the front of the arm in our illustrations because the arms are overhead and externally rotated.)

This physical arrangement of muscle attachments explains why the reclining arm-elevation exercise stretched your lats and pulled your ribs upward. When you were on your back and turned your palms up, you also rotated your upper arm bones outward. This rotation moved the attachment points of the lats on the upper arm out to the side, further winding the muscle around the bone, like rolling up thread on a spool. When you then lifted your arms overhead, you pulled the wound-up top ends of the muscles upward, away from the lower back. This caused the muscle fibers to tug on their lower attachment points on the bones of the back rib cage, pelvis, sacrum, and spine.

The first time you did the exercise, you probably allowed this tug to drag those bones upward along with the arms, and this tilted the pelvis, arched the back, and lifted the lower ribs off the floor. The second time, when you held your ribs down, you kept all of the muscle’s lower attachment points stationary, creating a stronger stretch. So one key to lengthening the lats is to stabilize the pelvis, lower back, and lower ribs as the arms move up and backward.

Another crucial action when stretching the lats is to rotate your arms firmly outward before you begin to lift them up, and to keep turning them the same way, but even more strongly, throughout every phase of the pose. Not only is this essential for achieving the stretch (because it keeps the upper end of the latissimus wrapped around the arm bone), but it also helps prevent injury to the tendon of one of your rotator cuff muscles, the supraspinatus. This muscle lies in a bony depression atop the shoulder blade. Its tendon passes through a tight space underneath a shelf of bone called the acromion process (which is part of the shoulder blade) and above the top end (head) of the humerus. The tendon then crosses to the outer side of the humeral head and attaches there.

Whenever you raise your arm, you run the risk of pinching the supraspinatus tendon between the humerus and the acromion. However, if you rotate your upper arm outward far enough before lifting it, you move the tendon out from underneath the acromion, so you can raise the arm freely without damaging the tendon. If the latissimus dorsi is tight, it will limit your ability to externally rotate your arm, which will increase your risk of pinching the supraspinatus tendon and, over time, you may develop a rotator cuff injury. This alone is reason enough to learn to lengthen and loosen your lats.

Here are three different ways to stretch the lats: a freestanding practice for relatively flexible students; a practice that uses props to stabilize the arms, suitable for all levels of students; and a variation of Pincha Mayurasana (Forearm Balance). In all these practices, the cardinal rules are to move slowly, never force, and back out of the pose if you feel a pinching sensation in your shoulder or upper arm.

Hit the Wall

The freestanding practice helps students whose lats are fairly loose to lengthen them even more. You’ll know that you belong to this group if your hands reached the floor before you felt much of a stretch when you practiced the reclining arm-elevation test at the beginning of this article. In that case, to get a strong lat stretch, you have to move your arms even farther back, so they end up behind your head.

This is impossible to do lying on the floor, but you can do it as follows. Stand with your back against a wall, externally rotate your arms as far as you can, and reach them overhead until you can press your palms into the wall. Step forward a few inches, maintaining the same alignment with your hands off the wall. Then—without arching your back, poking your lower ribs out in front, or moving your hips forward—reach your arms still higher and farther back until your palms press into the wall again. This backbending movement of the shoulders is the same movement required in poses like Downward-Facing Dog Pose and Urdhva Dhanurasana (Upward Bow Pose). To make it work, put extra effort into maintaining the rotation of your upper arms, because losing rotation would unwind the upper latissimus muscle from the humerus, putting slack on it.

Give Yourself Props

Whether your lats are loose or tight, the second method deepens your stretch more effectively by using props to align and stabilize your arms. Here is a good way to do this. Kneel on a folded blanket in front of a chair. Optionally, drape an unfolded sticky mat over the chair seat. Hold a yoga block in front of you, one hand on each short end. When you are in the pose, this block will keep your upper arms fully rotated by holding your forearms apart, so choose a grip that keeps your hands and wrists as far from each other as possible. Bend your elbows 90 degrees, and carefully place the backs of your elbows, near their tips, on the front edge of the chair seat, about shoulder-width apart or slightly closer. If you have trouble keeping your elbows on the seat, loop a strap around your forearms very close to the joint. Adjust the backs of your elbow tips so they rest as close as possible to the chair’s front edge without risk of sliding off when you put weight on them.

Walk your knees away from the chair until your trunk is parallel to the floor and your knees are directly under your hip joints. Draw your front lower rib cage upward so it does not sag toward the floor, and keep it there throughout the pose. Exhale, and being careful not to allow your elbows to slide off the chair, move your hips horizontally backward to lengthen your spine, slide your outer shoulders toward your ears, and draw your head away from the edge of the chair seat.

If there’s room, allow your head to hang down in the space between your trunk and the chair. Exhale again and move your hips back more. Press your tailbone slightly toward the floor to stabilize your sacrum, pelvis, and lower back; keep your ribs slightly lifted; and move your outer arms (triceps) toward the floor as far as you comfortably can.

If you experience discomfort in your shoulders, back out of the pose a little by moving your shoulders up away from the floor; then, as you reenter the pose, squeeze your elbow tips toward each other without actually sliding them closer together. (If this doesn’t relieve your shoulders, back out of the pose and seek help from a teacher.) When you have found a strong yet comfortable stretch, relax your outer armpits, the sides of your trunk, and the surface of your lower back all the way to your sacrum to allow the latissimus muscles to fully release, lengthen, and permit deeper movement.

Take it Upside Down

If you regularly practice inversions on your own, you can apply the movements from the elbows-on-the-chair pose to Pincha Mayurasana. To do this, place a block about six inches from a wall, broad side down. Loop a strap around your forearms just below the elbow to prevent them from separating beyond shoulder width (don’t strap the upper arms, or you won’t be able to drop your head between them) and place your hands, palms down, around the ends of the block. Kick up into the pose, then press your elbows and outer shoulders toward the floor to lift your body as high as you can. Tuck your chin toward the chest to move your head far forward between your arms. Look up toward your chest, draw your tailbone toward the ceiling, and pull your front lower ribs into your body. Finally, lifting your body still higher, move your shoulders horizontally away from the wall, beyond your elbow tips if possible.

That’s a lot to manage, but if you can do it, you’ll experience one of the most potent shoulder-opening poses on the planet. And even if your elbows remain chairbound, with regular practice, you’ll free your shoulders to reach toward the heavens for a lifetime.